Detonator



Patented Dec. 22, 1931 ROBERT D. BEAT'IY, OF BIRMINGHAM, ALABAMA :onronaron Application filed August 18, 1920. seriai'no. 475,900.

My invention relates to a device for detonating high explosives and adapted particularly for use in detonating explosives in holes of relatively great depth, as in rock =1. quarries and the like.

Theparticular object of my invention is p "spite the higher rate of detonation of the explosive in such a tube, there is still sufficient to provide a device of the character designated which shall be effective to produce detonation of a deep charge in such a manner 9 as to be as efiective as a relatively shallow charge.

In the accompanying drawings forming a part of this application,

Fig. 1 is a sectional view through a quarry face illustrating the effect of detonation of high explosives as heretofore practiced and as carried out by means of my invention;

Fig. 2 is an enlarged cross sectional view showing my invention in place in a hole ready for firing; and

Fig. 3 is a cross sectional view showing my improved detonating tube.

In the use of high explosives in certain work, such as in rock quarries, it often happens that holes are sunk to a depth of more than 100 feet and filled for a major portion of their depth with dynamite, or similar high explosive, and tamped on top the high explosive. The rate of detonation of dynamite varies from 3000 to 11,000 feet er second.

With a hole of such depth the lag in time between the explosion of the upper part of a charge of dynamite detonated at the top ahead of the lower portion is so great as to open fissures through the rock in the upper part and the force of the lower portion dissipates itself through these fissures.

This difiiculty led to the practice of providing a small tube of explosive having a higher rate of detonation than dynamite and adapted to be detonated from the top. his tube was lowered into the hole before the dynamite was packed in. its higher rate of detonation was depended upon to detonate the charge of dynamite in the lower portion of a deep hole before fissures had opened in the rock surrounding the upper portion to such an extent as to allow the lower portion of the charge to dissipate itself. As an example of such detonating explosive, there is to be loosened.

now sold to the trade, under the name of Cordeau, a continuous metallic tube filled with T. N. l., or similar explosive, and which may be cut into appropriate lengths and low 1 ered into a hole to be fired.

6a 'lnfiring deep holes, I have found that, de-

lag in time that a portion of the lower part of-a deep charge is dissipated through fisco sures, and there is left a toe or undisturbed portion of the rock represented by the area illustrated in Fig. 1, lying between the dotted lines A and B at the base of the rock face 10 6:, in order to overcome the before mentioned difficulties I began the practice of detonating atube of Cordeau, with dynamite packed around it, from the bottom of the hole by placing a detonating cap on the bottom of the tube before lowering it into the hole, attaching wires thereto for connection-to a suitable source of electrical energy and lowering the tube, cap and wires into the hole be fore packing with dynamite. Difficulties were at once experienced in maintaining the wires and cap in place during the lowering of the tube and packing of the hole, so that shots sometimes missed fire, making it necessary to detonate the charge from the top after surrounding holes had been fired, a dangerous and wasteful procedure.

in order to insure the detonation of charges such as have been described from the bottom, I designed and have since used the device illustrated in Figs. 2 and 3 of the, drawings. This device consists of a tube 11 preferably made of lead or a compound thereof whereby it may be wound upon drums and readily straightened out for use for the purposes described. The tube 11 is filled with an explosive 12 having a high rate. of detonation, such as'T. N. T. Surrounding the tube 11 is a casing or winding 13 made of fabric or other equivalent material and between the casing 13 and the tube 11, are interposed a pair of insulated wires 14 and 16 which are bound under the casingduring the process of manufacture so that the wires are always coextensive with the tube 11.

A detonating cap 17, having detonating wires 18 and 19 permanently secured thereto, is fitted over the end of the tube 11, the lower end of the tube 11 being bared sufliciently to accommodate the cap 17. The cap 17 is secured in place by means of a well known clamping device comprising a ring 21 crimped to thetube 11 at 22, as shown in the drawings, and having a plurality of fingers 23 extending downwardly aroundthe cap'17 and being drawn thereagainst by. means ofa ring 2 1. The wires 18 and 19 are then tied at 26 to the wires 14 and 16 surrounding the tube. The tube 11 and wires 14 and 16 are then cut off at or near the top of the hole and the hole is suitably packed in its lower portion with dynamiteshown at 27. The upper part istamped as illustrated at 28 and the holeis ready forfiring. By connection of the wires l and 16 to a suitable source of electric energy, not shown, the cap 17 is detonated followed by detonation of thehigh explosive '12 anduof the dynamite 27,

I have found that when shots are detonated in the manner just described, the lower part of. the face 10 shown in Fig. 1 is broken off along the line B thereby avoiding the toe left. by the explosionv of a charge from the top. downwards.

From the foregoing it willrbe apparent zthat; I. have devised an improved detonating .device which is simple of desi n, easy to :manufacture, and ,whichprovides a means 1 whereby a charge of high explosive in deep "holesp-may be readily detonated from the bottom. he wires l3 and 1& being bound integrally .with the tube 11 during the in length with the tube 11.

rdfi hilel haveshown my invention in but ,oneform, 1t Wlll be obvious to those skilled in the art that 1t is not so limited, but is susceptible of various changes and modifications, without departing from the spirit thereof, and I desire, therefore, that only such limitations shall be; placed thereupon as are imposed by the prior art'or as are specifilcally setforthin the appended claims.

What Iclaimis: 11. In a detonating device. a metallic tube ;,packed with high explosive and adapted for IDSGI'JCIOIL iii a hole to be fired, said tube being adaptedto-receive a detonating cap onthe end thereof, a fabric casing for the tube, and electricalconducting means disposed between the casing and the-tube and adapted for connection tothe detonating cap. 7

2. In a ,detonating device a metallic tube packed with high explosive and adapted for insertion in a hole to be fired,said tube being and wound on reels and carrying associated therewith and adapted to be cut off in lenghts therewith, wires for attachment to a percussion cap.

In testimony whereof I affix my signature.

ROBERT D. BEATTY. 

